Abrasive disc units



Jan. 28, 1964 H. l.. slANATAslo ABRASIVE DISC UNITS Filed July 26, 1962INVENTOR. HENRY L. GmNATASlo ited States Patent @ddee lld Patented Jan.28, 1964 3,119,263 ABRASEJE DESC UNITS Henry L. Gianatasio, @als Park,lil., assigner to lires-n Abrasives, lne., Addison, lll., a corporationof Iliinois Filed July 26, 1962, Ser. No. 212,617 2 Claims. (Cl. 51-195)This invention relatesy to abrasive disc units for abrading tools.

More speciiically this invention relates to an abrasive control discunit which -is adapted to be mounted on a rotatable arbor or shaft whichis adapted to be attached to the chuck of a portable electric handdrill, or other source of pov/er, for rotating lthe unit.

One of the problems experienced in the use of prior abrasive coated discunits, of the character referred to above,` has been the fact that therapid rotation of the abrasive coated disc units in contact with thework, and the pressure exerted thereon, as an incident to the operation,and the heat of friction developed therein, has tended to cause theabrasive coated disc to disintegrate under the heat and pressureincidental to the use thereof, particularly when it is necessary topress the abrasive coated disc into contact with a curved surface of thework, vas is irequently necessary in using such abrading tools on metalcastings, and the like.

Accordingly, .an object of the invention is to provide a new `andimproved `abrasive coated disc unit which in use overcomes theabove-mentioned and other difficulties experienced in the use of priorabrasive coated disc units of `a comparable character.

Another object of the invention is to provide a new and improvedabrasive coated disc unit embodying a flexible abrasive coated disc ofpaper, cloth, or the like, lhavin-g a flexible resinous backing ii-lrnthereon which imparts greater liexibility and greater heat resistanceand longer working or useful life to the new abrasive coated disc unit.

Another object of the invention is to p-rovide a new and improvedabrasive coated disc unit including `a ilexible abrasive coated disc ofpaper, cloth or like material, having a primary flexible resinousbacking film thereon and which is :co-extensive with the back snrface ofthe abrasive coated disc and a second and auxiliary reinforcing film ofsmaller diameter than the primary reinforcing )backing film on the rearsurface of the said abrasive coated disc and between the latter and theprimary iiex- -ible ii-lm for imparting additional strength andresistance to tearing and rupturing of the abrasive coated disc unit,particularly in the area thereof which is subjected to the greatesttendency to tear and rupture, namely, the area adjacent to the threadedferrule or rivet to which the abr-asive coated disc unit is attached.

Other and fur-ther objects of the present invention will be apparentfrom the following description and claims and are illustrated in theaccompanying drawing, which by Way of illustration, shows a preferredembodiment of the present invention 'and the principles thereof and whatl now consider to be the best mode in which I have contemplated applyingthese principles. `Other principles may be used and structural changesmay be made as desired by those skilled in the art Without departingfrom the present invention.

in the drawing:

FIG. 1 is an elevational View, partly in section, of an abralding ftoolembodying the nelw abrasive coated disc unit;

FIG. 2 is an enlarged sectional View on line Z-Z in FIG. l;

FlG. 3 is an exploded perspective view showing the parts embodied in thenew abrasive coated disc unit; and

FIG. 4 is an enlarged fragmentary sectional view of the area shown inFIG. 2 showing the manner in which the :abrasive coated disc and theprimary resinous backing lm and the secondary or auxiliary backing iilmare attached to the threaded ferr-nie or rive-t which is ernbodied inthe new abrasive-coated disc unit.

A preferred embodiment of the new abrasive-coated .disc unit isillustrated in the drawing, wherein it is gen;- erally indicated at 1i),and is shown as being used with and as a part of an abrading -tool whichcomprises a relatively small cylindrical metal shaft or arbor 11 havingan enlarged ruibber head or mandrel 12 mounted thereon at one endthereof, the mandrel 12 being substantially larger in diameter than theshaft v11, and the shaft 11 being designed to be inserted into the chuckof a portable electric hand drill, or lite source of power, as is wellunderstood in the art.

The rubber head or mandrel 12 has an enlarged annular flange portion i3lat its -forward end and this ilan-ged portion 13 forms or provides acylindrical cup or cavity 14 which is open at its forward end, for areason which will be pointed out presently.

The shaft 11 has a reduced screw threaded front end portion 1S which isarranged centrally within the cup or cavity 14 provided by the annulariiange 13 on the rubber cup or mandrel .12. The threaded vfront endportion 15 of the shaft 11 is adapted to be received in the threadedcentral base 16 of a ferm-le or rivet 17 which is provided at its frontend with -iiexible deformable clamping iianges 18 `which are arrangedradially therearound. As will be seen presently, the threaded ferrule orrivet 17 provides 'means for detachably atta-ching the newabrasive-coated disc unit 1@ to the parts 1-1-15-12 of an abrading tool.

The new abrasive-coated disc unit 11d includes a primary and disc-shapedflexible, resinous and relatively thin `abrasive-coated disc 19, whichmay be made of suitable material, such as paper, cloth, or the like, andwhich has an abrasive coating 2d on its face or front surface.

In the practice of the present invention, I provide a primary thin,disc-shaped, flexible, resinous lilrn 21 of iiexible polyester resinousmaterial, such as Mylar (Du Pont), or equivalent flexible resinousmaterial, which is co-extensive with the entire rear or back surface ofthe abrasivecoated disc 19-20, and this primary thin, flexible, resinousiilrn 21 is preferably in the order of about 0.003 inch thick, and is,heat-sealed or otherwise integrally bonded throughout its radially outerportion to the back or rear sunface of the abnasive-coated disc 19-20-The new abrasive-coated disc unit 1i? also includes a second and'auxiliary thin, plastic, resinous polyester film of disc-shaped form, ofthe same material (Mylar, Du Pont), or equivalent thin, iiexiblematerial, which is preferably in the order of about 0.010 inch thick,but is substantially smaller in diameter than the abrasive-coated disc1-9-20 and the primary, thin, iiexible resinous backing 21. This secondor auxiliary flexible backing film 22 is disposed between the rearsuriace of tlhe abrasive-coated disc .19 and the front sunface of theprimary, thin, flexible, resinous backing iilm 21 and i-s alsoheatsealed or otherwise integrally bonded to the back or rear surface ofthe abrasive-coated disc 19, and the radially inner port-ion of theprimary, thin, liexible, resinous back- 4ing film 21 is heat-sealed orotherwise integnally bonded to the rear surface of the secondary orauxiliary thin, flexible, resinous backing iilm 22.

In assembling the new abrasive disc uni-t a centrally arranged apertureZ5 is provided in the auxiliary iiexible resinous backing disc Z2 and acentrally arranged aperture 26 is provided in the primary, thin,resinous backing iillm 21, so that an annular marginal edge portion 24of the second or auxiliary backing film 22 surrounds the centralaperture 2.5I therein, and an annular manginal edge portion 23 in theprimary resinous backing lilm 21 surrounds the central aperture 26therein (FIGS. 3 and 4).

In assembling the parts of the new abrasive coated disc unit 10, theprimary resinous backing film 19 and the auxiliary backing film 22 arecut from stock to suitable size and disc-shaped form with the apertures25 and 26, respectively, formed centrally therein. The flanged front endportion 18 of the thereaded ferrule or rivet 17 is then inserted throughthe central aperture 26 in the primary backing film 21 and through thecentral aperture 25 in the auxiliary flexible resinous backing film 22.The clamping flanges 118 on the ferrule or rivet 17 are then peened ordeformed radially outwardly into engagement with the adjacent annularmarginal edge portions 24 of the auxiliary flexible resinous backingfilm 22 so as to clamp the annular .marginal edge portions 24 land 23 ofthe flexible resinous backing films 22 and 21 respectively, between thefront face 27 of the body of the ferrule or rivet 17 and the clampingflanges 18 thereon (FIG. 4).

The thus assembled abrasive coated disc unit may then be detachablyattached to the arbor or shaft 11 by threading the threaded front endportion of the shaft 11 into the threaded central lbore 16 in theferrule or rivet 17.

It has been found that the primary disc-shaped flexible resinous backingfilm 21 on the back or rear surface of the abrasive coated disc 19-20and the intermediate auxiliary flexible disc-shaped resinous backingfilm or washer 22 which is arranged between rear surface of the abrasivecoated disc 19-20 `and the front Isurface of the primary flexible,resinous backing lrn 21 and around the ferrule or rivet 17, 'gives thenew abrasive coated disc unit 1) greater flexibility and greater heatresistance, and longer working or useful life while, at the same time,providing greater resistance to tearing and rupturing of the abrasivecoated disc 19-20 in use, 'and particularly in the area thereof which issubjected to the greatest tendency toward tearing and rupturing, namely,the area adjacent to the ferrule or rivet 17.

It will thus be seen from the foregoing description, considered inconjunction with the accompanying draiwing that, ythe present inventionprovides a new and improved abnasive coated disc unit having thedesirable advantages and characteristics and accomplishing its intendedobjects including those hereinbefore pointed out and others which areinherent in the invention.

I claim:

1. An abrasive-coated disc unit for attachment to the shaft of a powerdriven rotary abi-lading tool comprising `a flexible abrasive-coateddisc having `an uninterrupted front surface entirely covered with anabrasive coating, a second and auxiliary thin flexible resinous backingdisc having a central aperture therein, said second and auxiliary thinflexible resinous backing disc being attached ccntrally to the rearsurface of the said ilcxible abrasivecoated disc and being substantallysmaller than said abrasive-coated disc, la flexible resinous backinglilm having a central aperture therein and attached to the second andauxiliary thin flexible resinous backing disc, and means directlyattached to the said second and smaller auxiliary thin backing disc andto the said flexible resinous backing film adjacent the said centralapertures therein for detachably attaching the said abrasive-coated discunit to the shaft of a rotary power driven abrading tool.

2. An abrasive-coated disc unit as defined in claim l-iin which the saidmeans for detachably attaching the said abrasive-coated disc unit to theshaft of a rotary power driven abrading tool is in the form of iaferrule or rivet having a centrally arranged threaded bore therein forthe reception of the threaded end portion of the said shaft of anabrading tool, and in which the said ferrule or rivet has a front endportion provided with a series of radially arranged clamping flangesextending radially outwardly from the said centrally arranged threadedbore in the said ferrule or rivet and into engagement with the marginaledge portions of the said centra-l :aperture in said second and'auxiliary flexible resinous backing disc and binding the marginal edgeportions of the said second or auxiliary flexible resinous backing discand the marginal edge portions defining tlle `said centrally arrangedaperture in said flexible resinous backing film between the saidclamping flanges .and the body of the said fer-rule or rivet.

References Cited in the file of this patent UNITED STATES PATENTS2,320,139 Kirchner May 25, 1943 2,520,763' Goepfer-t et al Aug. 29,195() 2,567,782 Rhees Sept. 1l, 1951 2,996,851 Gianatasio Aug. 22, 1961

1. AN ABRASIVE-CAOTED DISC UNIT FOR ATTACHMENT TO THE SHAFT OF A POWERDRIVEN ROTARY ABRADING TOOL COMPRISING A FLEXIBLE ABRASIVE-COATED DISCHAVING AN UNINTERRUPTED FRONT SURFACE ENTIRELY COVERED WITH AN ABRASIVECOATING, A SECOND AND AUXILIARY THIN FLEXIBLE RESINOUS BACKING DISCHAVING A CENTRAL APERTURE THEREIN, SAID SECOND AND AUXILIARY THINFLEXIBLE RESINOUS BAKCING DISC BEING ATTACHED CENTRALLY TO THE REARSURFACE OF THE SAID FLEXIBLE ABRASIVECOATED DISC AND BEING SUBSTANTIALLYSMALLER THAN SAID ABRASIVE-COATED DISC, A FLEXIBLE RESINOUS BACKING FILMHAVING A CENTRAL APERTURE THEREIN AND ATTACHED TO THE SECOND ANDAUXILIARY THIN FLESIBLE RESINOUS BACKING DISC, AND MEANS DIRECTLYATTACHED TO THE SAID SECOND AND SMALLER AUXILIARY THIN BAKCING DISC ANDTO THE SAID FLEXIBLE RESINOUS BACKING FILM ADJACENT THE SAID CENTRALAPERTURES THEREIN FOR DETACHABLY ATTACHING THE SAID ABRASIVE-COATED DISCUNIT TO THE SHAFT OF A ROTARY POWER DRIVEN ABRADING TOOL.